Internet Security

I have had AVG internet security on my pc for a few years, but went right off it several months ago, when a "thorough scan" stalled and really messed up my computer. I was unable to rectify the problem, even with some remote assistance from AVG. There were two sessions on the pc, and my wife's session was ok, so I was able to create another new session for myself, but I did not wish to continue with AVG, and, so I thought, had communicated that fact to them. I've just had an email from them, however, telling me they are going to renew my subscription and they will charge me £72.99 at the beginning of November. 
Logging into my AVG account shows "no subscriptions" and a list of my previous subscriptions shows nothing that is due to renew in November. I'm trying to make sure that any existing subscriptions are definitely cancelled, but online  "Support" keeps sending me round in circles. Please, please, can somebody tell me how to cancel this because I do NOT want to renew.
Thank you
Hi Les,

We have replied to your other post: http://suppor.avg.com/answers?id=9060N000000gBtd .
Please communicate from the other post to get quick assistance.
Thanks.
Hi Les,

We have replied to your other post: http://suppor.avg.com/answers?id=9060N000000gBtd .
Please communicate from the other post to get quick assistance.
Thanks.